( function. Topical treatments inclu...)A new target for painkillers

Topical treatments include capsicum cream derived from chili peppers, but they usually are not very effective.

"There really is no highly effective treatment available for this kind of severe pain, so having a new way to treat it is exciting," McIntosh says. If the new discovery eventually leads to a new pain drug that is combined with existing treatments, "you may be able to reduce the pain to a lower level than ever before. No one drug is going to fully treat all pain, so having a new way is like having a backup catcher if the first catcher misses the ball."

How the Study was Performed

The toxins in the study come from two cone snail species that eat worms, unlike relatives that eat fish or snails and occasionally deliver a fatal sting to a human fisherman.

-- RgIA is from the species Conus regius, which measures 1.6 to 2.8 inches in length and lives from Georgia southward along Central America to Brazil's central coast.

-- Vc1.1 is from the species Conus victoriae, which measures 1.4 to 2.8 inches long and lives off portions of Australia.

RgIA and Vc1.1 fit like keys into lock-like alpha9alpha10 nicotinic acetylcholine receptors, which are found on nerve cells and are in the family of receptors activated by nicotine from cigarette smoking.

Alpha9alpha10 nicotinic receptors are found in a variety of body tissues, including white blood cells and the dorsal root ganglia ?a group of nerve cells near the spine and involved in pain transmission.

The new study showed alpha9alpha10 nicotinic receptors provide a previously unknown route to pain relief. McIntosh says a patent is pending on this new mechanism.

One form of severe nerve pain is known as sciatica, and occurs when a herniated disk in the lower back causes pain to one or both sciatic nerves, which extend from the lower back to the hips, buttocks and back of the thighs.

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Source:University of Utah